1. Field of the Invention
The present invention relates to a device, a system, a method, and a computer-readable recording medium having a computer program for controlling printing.
2. Description of the Related Art
Conventionally, there have been developed image forming apparatuses provided with a clear toner, which is a colorless toner including no color material in addition to four colored toners of cyan (C), magenta (M), yellow (Y), and black (K). A toner image formed with such a clear toner is fixed on a transfer sheet, on which an image is formed with CMYK colored toners. As a result, a visual effect and a tactile effect (referred to as a surface effect) are produced on the surface of the transfer sheet. The surface effect to be produced differs depending on the type of the toner image formed with the clear toner and the way to fix the toner image. Some surface effects simply provide gloss, whereas some surface effects suppress gloss. Other examples of the surface effects may include: a surface effect applied not to the entire surface but to a part thereof; a surface effect that forms a texture and a watermark with a clear toner; a surface effect that provides surface protection; and a surface effect produced by a dedicated post-processing device, such as a glosser and a low-temperature fixing device, performing post-processing besides by fixing control. In recent years, as disclosed in Japanese Patent Application Laid-open No. 2011-150158, for example, a technique of providing gloss by causing a clear toner to adhere to only a desired portion on a part of a surface has been developed.
Furthermore, as disclosed in Japanese Patent Application Laid-open No. 2011-43683, for example, gloss is influenced by surface roughness of an image formed on a recording medium, that is, is influenced by surface irregularities that are generated by CMYK toners. This means that the degree of gloss is not always increased in accordance with a density of a clear toner simply.
That is to say, smoothness of a surface of an image is required to be controlled in order to provide gloss. For controlling the smoothness, image data of a clear toner plane as image data for forming a toner image with a clear toner needs to be created in accordance with density values of CMYK for pixels to which the clear toner is made to adhere, presence or absence of a post-processing device that is connected to an image formation apparatus, and a type thereof. In addition, contents of the image data of the clear toner plane, the number of pieces of image data of the clear toner plane that are created, control of a printer, control of the post-processing device, and the like are needed to be adjusted finely. As general characteristics of glossiness, glossiness tends to be high on white paper, particularly, solid portions and glossiness tends to be low on portions with intermediate colors. Based on the characteristics, processing of providing even glossiness on the entire surface by controlling an amount of the clear toner so as to obtain target glossiness on the solid portions has been considered to be needed and already known.
There is the following conventional method of adjusting the glossiness as disclosed in Japanese Patent Application Laid-open No. 2007-186593. That is, gloss difference is eliminated by controlling an amount of the clear toner itself. The method, however, has a problem that the clear toner is more expensive than colored toners and print cost is increased.
Furthermore, a method in which a feeling of strangeness of the gloss difference is reduced by limiting portions on which the clear toner is used has been also proposed as disclosed in Japanese Patent Application Laid-open No. 2006-168107. The method can reduce the cost but has a problem that generation of irregularities on a printed material as a result has to be allowed.
In view of the above-mentioned circumferences, there is a need to provide a device, a system, a method, and a computer-readable recording medium having a computer program for controlling printing that are capable of improving print quality by adjusting amounts of colored color materials and eliminating gloss difference on an entire surface, and reducing cost of a clear color material.